Protective Effects of Efonidipine, a T and L-Type Calcium Channel Blocker, on Renal Function and Arterial Stiffness in Type 2 Diabetic Patients with Hypertension and Nephropathy

Aim: The three types of calcium channel blocker (CCB), L-, T- and N-type, possess heterogeneous actions on endothelial function and renal microvascular function. In the present study, we evaluated the effects of two CCBs, efonidipine and amlodipine, on renal function and arterial stiffness. Methods: Forty type 2 diabetic patients with hypertension and nephropathy receiving angiotensin receptor II blockers were enrolled and randomly divided into two groups: the efonidipine group was administered efonidipine hydrochloride ethanolate 40 mg/day and the amlodipine group was administered amlodipine besilate 5 mg/day for 12 months. Arterial stiffness was evaluated by the cardioankle vascular index (CAVI). Results: Changes in blood pressure during the study were almost the same in the two groups. Significant increases in serum creatinine and urinary albumin and a significant decrease in the estimated glomerular filtration rate were observed in the amlodipine group, but not in the efonidipine group. On the other hand, significant decreases in plasma aldosterone, urinary 8-hydroxy-2'-deoxyguanosine and CAVI were observed after 12 months in the efonidipine group, but not in the amlodipine group. Conclusions: These results suggest that efonidipine, which is both a T-type and L-type calcium channel blocker, has more favorable effects on renal function, oxidative stress and arterial stiffness than amlodipine, an L-type calcium channel blocker.